


Heart-shaped box

by Anonymous



Category: Supernatural
Genre: Always Female Sam Winchester, F/M, First Time, Weecest
Language: English
Status: Completed
Published: 2021-02-03
Updated: 2021-02-03
Packaged: 2021-03-15 02:41:20
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 3,992
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29181945
Author URL: https://archiveofourown.org/
Summary: Dean’s mouth is very dry, and he’s getting very uncomfortable in his pants. He has never thought about this - never with so much clarity and awareness, at least, but Sam is a virgin. Sam is a girl. Sam is almost a woman.
Relationships: Dean Winchester/Sam Winchester
Comments: 8
Kudos: 88
Collections: Anonymous





	Heart-shaped box

**Author's Note:**

> My contribution to the GirlSam agenda.  
> I didn't have a beta, so if you catch a mistake, be so kind as to let me know so I can fix it ;)  
> Please note this story is set in the 90's, so some lines reflect stuff from that time, etc.

Sam wanted to catch a movie, Dean wanted to pick up chicks at the bar, and John wanted them to get the hell out of this town. In the end, the chilly evening has them enjoying the heating in the nicer-than-usual motel, eating cold leftover pizza and drinking cheap booze. There’s something black and white on tv, the volume pleasantly low, lights on but not too bright, and he and Sam are on the couch just talking about inane shit while their father half-listens, occasionally comments to tease. Sam is trying a little too hard to impress Dad, as usual, and John is unusually good humored, and Dean’s heart is so full with affection for his family that, in that moment, he can almost believe that all is right with the world.

At some point John’s eyes get distant, and Dean knows they have lost their father for the evening. Their father has a couple of personal ghosts that never leave him alone for long, and when they show up, there are only a handful of things that can help exorcise, Dean knows by now. As expected, Dad gets up, tells them he’s going to hit a bar, and just like that, leaves. In all fairness, it's been a while for both of them - Dean longer than Dad, if only because he enjoys hanging out with Sam enough to skip night-stands once in a while.

Sam sits next to him in silence, a little sullen. Dean elbows her gently. “What?”, she slurs, a little drunk.

“He needs it, you know?”

“Booze? We have it here. He just got tired of us.”

“No, dumbass. Not booze. I mean, you know. A girl, to blow off some steam.”

Sam’s frown eases out. “Oh.”

Dean throws his head back, enjoying the light buzz of alcohol. “Let him have it, Sammy. A man needs it.”

Sam scoffs. “And girls don’t?”

“Gross.”

“Oh? Really? Girls are _gross_?” Sam’s eyebrows shoot up in her forehead, all sarcasm. She’s such a little shit sometimes. Dean loves her so much.

“Talking to your sister about it is gross. You do whatever you need to do, just don’t tell me about it,” he says. Sam doesn’t sass, so he replays what he just said in his mind, and freezes. ‘ _Do whatever you need to’_ ? Sammy, his sister? Well, what if she _is_ doing whatever she needs to? Is Sammy having sex? Is Sammy having sex with random guys at school? Is Sammy _blowing off steam_ like he does and Dad does? 

Does Sam _need it_ like they do?

He’s on the verge of a violent emotion when he looks at her, the question on the tip of his tongue, but she beats him to it. 

“You’re such a jerk. It’s not like it’s easy for girls.”

Huh. Relief. “Yeah?”

“Yeah. Like. If you’re a man, you just-” she makes a hand motion that is not figurative in the least, but he gets it, feeling it right between his legs, he _gets it_ , “and it’s done. You - you come, sometimes it’s bad and sometimes it’s worse, but whatever. But for a girl, it hurts, you know? Everyone says it hurts, the first time. And like, I don’t know. It’s complicated. I want, I want to, but,” she pauses, and risks a glance at Dean.

Dean’s mouth is very dry, and he’s getting very uncomfortable in his pants. He has never thought about this - never with so much clarity and awareness, at least, but Sam is a _virgin_. Sam is a girl. Sam is almost a woman. 

_She just wants to talk. Don’t make it weird. Don’t make it weird, don’t make it weird_ . Dean keeps telling himself, but it is already weird, when it’s been several seconds and he hasn’t said anything back, and he’s just staring at Sam, swallowing spit. Sam is not a child anymore, hasn’t been for a while. This is what he has been afraid of since he helped her buy her first bra, he thinks as he tries to decipher the volume of her boobs under the Nirvana hoodie he has given her so much shit for wearing, even as he’s screaming at himself to stop doing it, and he’s warning himself that that’s his _little sister, his baby sister_ , but his cock is taking it as encouragement rather than admonishing, and Dean is tenting, my god; all of a sudden Dean is hard and uncomfortable in his pants thinking circular thoughts of how Sam is a girl and Sam is a virgin and Sam is not just a girl, Sam is _Sam Winchester_ . Sam is John’s girl, and Dean’s to take care of. _Do whatever you want?_ What had possessed him to say that?

Sam hasn’t noticed a thing. She must not, _cannot_ have noticed how worked up he was, how close to panicking, because she sits up and throws her head back, baring her neck and looking at Dean now, and it can’t be suggestive because there’s no way his baby sis is doing this on purpose to provoke him, no way she knows what she’s doing when she licks her lips slowly and picks up the conversation right where she left it.

“Any girl will do for you and dad to blow off steam, or whatever you call it. But for girls, like, we want a guy who knows what he’s doing, but we don’t want a creep, or somebody who’s going to say shit later. We want a guy who cares, you know? It can’t just be anyone, Dean. The only guy I know who cares is you.” And Dean hears the tremor in her voice, he can’t think of his father, now, his father picking up a girl at a bar, his father bringing a girl to the backseat of the Impala and _god_ , he’s not going to be gone long enough, not nearly long enough, and the rational part of his brain is screaming _long enough for what?_ and _Don’t you dare, Dean Winchester, you will cut your dick off before you dream of touching your sister like that,_ but he’s gone. There is so much going on in his brain and with his body and he just sits there, frozen, struggling to breath, eyes trained on Sam’s pink cheeks and wet lips and wise eyes looking directly into his and she knows. _She knows_. He would be panicking if he wasn’t so fucking horny, gone stupid with want.

“Dean?”

Her voice is so small that it drags out an answer from him. “Yeah, Sam?”

“Do you understand?”

They look at each other. The white noise of the TV fills his head, empty of thoughts. 

In slow motion, Dean’s hand moves to Sam’s knee. He doesn’t dare break eye contact as he presses down gently and then pulls it towards him, very gently, very slowly, spreading Sammy’s legs open.

“Do you. Sam,” it’s such a fucking effort to talk, but Sam understands his meaning. She always does, his baby sister, so fucking smart, bless her.

She nods minimally. Then she kisses him. 

It’s chaste, but Dean moans loudly, his hips jerking, and it’s all he can do not to shove Sammy back against the couch. He’s using all his self control because his little sister deserves it, so he tries, he really tries to go slow, and it’s for nothing, because within seconds he is sucking Sammy’s tongue, invading her mouth and going at it with too much fire, he doesn’t want to scare her, but _god, god, go-_

Sam gasps when Dean touches her through her sweatpants, which should be an indication of how desperate she is, and he is desperate too but there’s a clock ticking on the back of his mind and he might be so many horrible things right now, but he will always be a good big brother. He might not be completely damned, if he at least makes it about her. So he pulls Sammy’s sweatpants down and off, and kneels between her legs, and touches her where she is so wet that her undies are completely soaked. _Take it easy_ , he knows, _he knows_ , but Dean can’t help shoving his face and filling his lungs with the obscene smell of baby sister cunt, and above him she echoes the noises he’s burying against her soiled underwear. Sam grips his hair and jerks her hips, and calls out his name and Dean knows, _knows_ he will willingly walk into hell for a moment in this heaven. When he looks up, Sam is looking right back at him, her eyes glassy with lust. 

Dean is trapped in that gaze. He can’t look away. There isn’t a single thought in his mind; in that moment, there is only body, skin, and his heart pumping his cock full of the same blood that flows in her veins. _Kin of my kin, blood of my blood_.

He takes her underwear down, slowly. Sam spreads her legs, and he wants to look. He wants to look, but he can’t tear his gaze away from hers.

He runs a finger along her dripping lips. He uses his thumbs to spread her open, and slowly, deliberately, dips in, and gives her cunt a sloppy kiss. 

Her body tenses and she moans, screwing her eyes shut, freeing Dean from the spell so he can concentrate on what he wants - and what he wants is his sister stretched, open, wet and wanting; he wants her satisfied, he wants her his, he wants inside and never wants out. Distantly he remembers there is a Nirvana song about this, he’s pretty sure; he almost asks Sam. Dean licks her with intent, neglecting the clit at first so that when he gets to it she gives a full body jerk and almost crushes his head between her thighs. She does it again when Dean carefully slides a finger in her, and then a second one, and between that occasional crushing pressure and how hard it is to breathe when he’s sucking her with all he has, he thinks that dying like this would not be so bad, it would not be bad at all. 

Not bad at all until John came back and found them. Dean, dead by sister-fucking. His father would bring him back to life just to kill him again. This thought should make him wither, make him impotent for the rest of his life. Instead, he is so hard it almost hurts. He sucks on his little sister’s clit with the devotion of a martyr.

“Dean!!” Sam cries sharply and clamps her thighs when he jerks his hand harder, burying his fingers inside her to the knuckles, and he knows she’s coming, riding it _hard_ . He made his baby sister come with his name on her lips, and for a moment of panic he thinks, _this is not happening, this is not happening_ , he can see John snarling at him from the door, picking up a gun and shooting him dead for defiling his baby girl, Mary’s baby, except Sam is now _his_ baby girl, he’s laying claim. Dean’s so sick, he’s so fucking _sick_ , but he moans into Sam’s cunt as he brings one hand down around himself and a couple tugs are enough for him to come in his pants, too, lapping at her wet cunt lazy and messy like a stupid dog. Dean lays his head cheek-down on her thigh. Sam’s hand on his hair is trembling as she caresses his scalp, and Dean can’t believe it. He can’t believe he has this. He breathes her scent in deeply again, and the room air is cool against the sloppy wet mess that is his face. He opens his eyes and notices his fingers are still buried in her. 

He curls them, and she stills. He adds a third one, and she gasps his name, spreading her legs as far as they will go. 

His knees are hurting and his arm is sore from the position, but more importantly, his cock is still hard and dry of little sister cum. The longer this goes on, the more Dean will hate himself, but he’s gotta see it through. Dean doesn’t know what exactly Sam had in mind when she talked about sex, but nothing in their life is real unless there is blood, and he needs to see it. More than he needs to cum inside her and make her come on his cock and make her say his name like that again before their father returns - and he _really_ needs it - he needs to see her blood on his cock.

He takes it up again, working his fingers, and she’s loose and wet, sloppy, dripping with girlcum and drool. Distantly he realizes he hasn’t even seen her breasts yet, but the awareness of John’s possibly imminent return keeps him focused on the goal. He thought he was going to die if their father caught them because John would kill him, but now he thinks he’s more likely to die if he doesn’t get his dick inside his little sister. 

The symmetry of their feelings is astonishing. He gives Sam’s clit a broad lick and she jerks his head up, looks him in the eyes and it sounds like a command but it’s really a plea when she says, “Dean!”

He doesn’t know how he finds his voice to answer, more animal than human, “Yeah, Sammy?”, as he works his fingers inside her, teasing now, stretching her nice and good.

“Please, Dean?”

Jesus. His jaw is sore but he can’t help grinning. His sister is so perfect like this, and if there is a god Dean wouldn’t know whether to punch him or to thank him for making Sam like this, for giving Sam to him. His baby sister. He’s going to be sick with how much he enjoys this. “Please what, Sammy?”

She whines high-pitched, “Dean! Come on!”, and Dean chuckles in disbelief, overcome with affection again. Her hands are tugging him up, urgent, so he goes because he will never deny her anything when she begs; Dean kisses her deep, giving her a taste of her own cunt. He is _so fucking hard_ when her hands undo his zipper, he knows he is this stupid now because all the blood ran from his brain and went to his cock. Her eyes are closed but his are open so he can memorize her face as he kisses her, tongue-fucks her mouth, indulgent and nasty. He doesn’t want to hurt his baby sister, ever, but an animal part of him would like to see how deep he can get his tongue in, if he can literally get in her throat, fill her up completely on all fronts. It’s a crazy thought, but it has his hips jerking involuntarily. _God_ , he wants her. 

Sam holds his cock and jerks it clumsily, once, twice, and hot as it is, Dean gently removes her hand. They’re lying on the couch now, which Dean knows it’s a bad idea, they should take it to the bed which is easier to clean, but, but-

He’s lining up the head of his dick against Sam’s cunt, and she’s begging him to get on with it, her lips moving against his ear. Dean loves it, loves how close they are, but it won’t do. So he untangles himself from her embrace and props himself up so he can look directly into her face and see her reaction as she takes him - her first time. Sammy’s first, god help him, Sammy’s only. Sam’s puppy eyes are pleading with him, now. Her perky nose, her pointy chin, her furrowed brow; one of Dean’s fingers is tracing it adoringly, and he doesn’t mean to tease, he tries to tell her that, but, it’s her, it’s his Sammy. He was a fool before, because if there is a god he has no place in motel rooms. No god, no heaven and no hell, no father and no mother: his world has become the promise of Sam’s warm cunt. 

Dean pushes in, slowly. Pushes the tip in, and Sam gasps, then swallows, then moves her hips, impatiently. He thrusts shallowly, breaching that heavenly warmness inch by tight inch and thanking fuck he has already come once. He can’t let his Sammy down, he will never let her down, he thinks as he memorizes the way she gasps when he thrusts, the special frown she wears, the desperation in her eyes gaze locked into his and her hands grab his arms, her face all wet with tears, drool and her own cum where he slobbered all over it earlier. He bottoms out and she fits him perfectly, like no other girl before, because no other girl was made for him like Sam was. He feels thick, stupid with desire. 

He feels like coming home.

“Sammy?”

She nods, biting her lips.

“Sammy, are you okay?”

“Y-yeah, Dean.”

“Sammy.”

“Dean?”

 _I love you_. It chokes on his throat. Instead he grabs her hand and slowly brings it down to where they’re joined, and her eyes widen. Their hips are pressed so close together that there is barely any space for her hand, but she keeps it there, crushed between their bodies, tentatively touching the place where her lips are spread wide for him, such a perfect fit. 

“I’m here, Sammy,” he tells her pathetically, moving their hips together without pulling away, rocking them for her benefit, so she can slowly get used to it. So this can be good for his baby girl, as good as she is for him. “I got you,” Dean says, and he thinks he’s losing it a little. 

“I- I know, Dee, I know,” she says, bringing a hand to his cheek, but keeping the other exactly where he put it. _Oh, Sammy. My Sammy, Sammy, Sammy-_

Dean moves back and pulls out very slowly, sliding out of Sam’s cunt and Sam’s fingers right where she kept them. Then, he gently pulls her hand and inspects it, and there it is. Her blood, sticky with her other juices. _My blood, too. Blood of my blood_. Dean shows Sam her own hand.

She stares at it for a heartbeat, fascinated. Then she looks at Dean dead in the eyes and, slowly, drags her tongue along the stain on her fingers. 

Dean whines and pushes into her again, like something in him finally snapped. He buries his head on Sam’s neck and thrusts with abandon, like an animal, like he is the virgin popping his cherry and not her, and he just needs _in_ so badly that he can’t even think of making it good for her - not until she takes his hand, in a mimic of his earlier gesture, and brings it to her clit, and he shakes his head, “Wanna make you come on my cock alone, Sammy,” and he’s caught off guard when she insists on the gesture and says, “you can do that next time, Dean, please, I just wanna come, I just wanna, please,” and ‘ _next time_ ’ is what has Dean groaning and acquiescing, bringing his fingers down and tipping her over the edge and fucking her through her second orgasm of the night while he tells her, lips to ear, “yeah, baby girl, like that, taking it so good, coming on your brother’s cock, so good for me, so good for me,” and a whole lot of nonsense tumbling uncontrollably from his mouth until Sam pulls his face, lazily, and kisses him, then her face opens up with a smile.

Not a grin, but a bonafide smile. Sammy’s face tired and well-fucked and lit up all for him, for the good fucking he gave her, for how good he popped her cherry and took care of his baby sister’s needs like the good big brother he is. That’s what tips him over the edge, and he’s looking straight into her eyes as he comes hard, painting her insides, hips erratic but not slowing down until a good moment later, when her cunt has sucked him dry of all the cum he had been saving up just for her, just for his Sammy.

The next moments are hazy. He stays on top of her, catching his breath, and he’d feel bad about if she weren’t so strong, his Sammy. Eventually she squirms and sits up, and he finds his head on her lap, close again to her cunt, and the smell of what they just did makes his cock stir again, despite how tired he feels. How can you long so badly for something that is right next to you, that you just had? 

Maybe it’s knowing that you should never have had it, and should never have it again.

He kicks his pants and boxers down, feeling suddenly hot and uncomfortable in them. Logic thoughts are coming back now, in full force, and he fights off the mild panic rising steadily. 

_Dean came inside his little sister_ . God. He feels sick, and sicker when he realizes how the thought arouses him, his cock definitely interested now. He wishes he hadn’t stripped, he doesn’t want Sammy to see it. _What if she gets pregnant, Dean, then what?_ , he finally acknowledges the thought, and the edge between panic and disgust and arousal blurs more. He’s gonna ruin their lives because he couldn’t keep it in his pants with his own sister. _His own sister_ , he thinks, and shifts his leg, disgruntled at how horny that thought makes him. _Disgruntled_. Disgust rides like a fucking rollercoaster, up and down, up and down.

“Dean, I,” Sam starts, and he freezes. Her hand is very gentle against his scalp. Dean is slowly but surely getting hard again, and he wants back in right _now_ , but reality is a sledgehammer pounding against his conscience. “I’m not. I’m not going to get pregnant. I just had my period, so I’m not. You know? Don’t worry. Sorry I didn’t tell you before. It was just… You know.”

Dean breathes more easily. He wants to press a kiss against her thigh, but finds himself at a loss. He needs to face the facts, and the facts are: he’s going to do something very stupid again very soon if he doesn’t get up now. He has fucked up enough for a night, enough for a whole lifetime. He needs to get up and think of the right thing to say, find out how to atone. Find out how to feel truly guilty, because _fucking christ_ , he doesn’t.

“Thank you,” Sam whispers. Dean feels sick.

“Sammy,” he starts, but can’t find the words to go on.

“Yeah,” she answers, nonetheless. “We should clean up before dad comes back. But he took the car, Dean. He’s not going to be back so soon.”

They don’t move. 

Dean turns over so he still has his head on Sam’s lap, but faces her body, now. He breathes in deep. Her breath catches. He looks at her, dead serious. 

But Sam doesn’t look any different from how she did hours before. She still looks like his baby sister. She seems deep in thought, but very aware, like she’s trying to anticipate what Dean will do next.

“Hey, Sammy?”

“Yeah, Dean?”

 _I love you so fucking much._ “Take off your shirt?”

There is a pause. She’s looking at him straight in the eye. She’s not grinning, but there is something increasingly mischievous in her eyes, and if he wasn’t hard before, he for sure is now. 

Slowly, Sam takes off her sweatshirt. Impatient, Dean sneaks up a hand under her shirt and finds out that she’s not wearing a bra, and that his hand fits perfectly over her breast. He wonders at how their bodies match perfectly everywhere, and gives the nipple a tentative pinch.

Sam yelps and her thighs tremble. 

Despite himself, Dean grins.


End file.
